Gas analysis apparatus



Nova 22, 1949 L. s. GALSTAUN ET AL, 2,433,812

GAS ANALYSIS APPARATUS Filed April 10, 1945 3 Sheets-Sheet 1 ATMOSPHERE 70 CONTROL CIRCUIT 343 -aAs DEL/VERY INVENTORS LIONEL S. GALSTAUN DELBERT J. THOMAS 348 A 7' romvm NOV. 1949 L. s. GALSTAUN ET AL 2,488,812

GAS ANALYSIS APPARATUS Filed April 10, 1.945 3 Sheets-Sheet 2 l-w? /4/ 442 /48 8 OUTPUT INVENTORS T LIONEL acmsmwv DELBERT 0. THOMAS ATTORNEY Nov. 22, 1949 L. s. GALSTAUN ET AL 294389332 GAS ANALYSIS APPARATUS Filed April 10, 1945 s Sheets-Sheet 3 figsi a E AC. POWEH D. 6. POWER JNVEIVTORS L/O/VEL 5. GALSTAU/V 0545/5/97 D. THOMAS A T TQR/VEV Patented Nov. 22, 1949 bliliil STATES GAS ANALYSIS APPARATUS Application AprillO, 1945, Serial No. 587,633

3 Claims.

The invention, in general, relates to governing the flow of fluids and more particularly relates to means for auton1.-,tically and recurrently reversing the 160w of fluids in a closed system.

While the hereinafter described invention is entirely suitable for adaptation to a variety of types of equipment designed for handling, measuring or moving gases or fluids, including Toepler pumps and sinlilar apparatus, the invention has especially been devised for adaptation to Orsat analyzers and similar laboratory precision equipment. For purposes of explanation only, the invention will be particularly described in the latter environment.

A primary object of our invention is to provide automatic reversing control apparatus thereby eliminating the requirement or manual operation of equipment having as its essential function the alternate reversal of the dew oI" fluids through a chamber or series of chambers.

More specifically, it is an object of this invention to provide apparatus of the aforementioned character for autoinaticaliy and repeatedly causing a confined gas to over or through an absorbing medium, such as in an Orsat analyzer for gases, without carry-over of liquids confined in the syste A still further object of our present invention is to provide automatic reversing control of the indicated nature which affords the operation of equipment of the aforementioned character, such as an Orsat analyzer, or other equipment for measuring the volume of a given gas or fluid absor ed by a liquid, in a minimum of time and with a minimum of labor.

Other objects of the invention, together with some of the advantageous features thereof, will appear from the -following description of a preferred embodiment as well as certain modified embodiments of our invention which are illustrated the accompanying drawings. It is to be understood that we are not to be limited to the precise embed, .ents shown, nor to the precise arrangement of the various parts thereof, as our invention, as defined in the appended claims, can be embodied a plurality and variety of forms.

Referring to the drawings:

Figure 1 is a diagrammatic view of a portion of a preferred embodiment of our invention, as applied to the operation of an Orsat gas analyzer.

Figure 2 is a diagrammatic view of an electrical circuit forming a part of the preferred embodiment of our invention illustrated in Figure 1.

Figure 3 is a diagrammatic view of a modified electrical circuit adapted to be incorporated'with Figure 5 is a diagrammatic View of a portion of a preferred embodiment of our invention, as

operation of a Toepler pump, the ratus being adaptable for incorporation i any one of the electrical circuits shown in gures 2, 3, l or 6.

Figure is a diagrammatic view of still another electrical circuit for connection with those partial embodiments of our invention illustrated in Figures 1 or 5, or like equipment.

In its preferred form, the automatic reversing cont 01 Of our invention preferably comprises apparatus confih g fiui s, such as a gas and a liquid, in a closed system, and means for automatically and repeatedly moving the fluids within the system first in one direction and then in the other direction.

With particular reference to Figures 1 and 2 of the annexed drawings, it will be observed that We provide our preferred embodiment of our illustrated up invention, as applied to an Orsat gas'analyzena.

plurality of absorption units integrally connected together for communication with one another, each consisting of a reservoir tube M and an absorption tube 42. On each of the reservoir tubes ii is mounted, so as to extend within the same to adjacent the bottom thereof, a pair of electrodes 11 which are connected into oppositesides of one of the electrical circuits hereinafter more specifically described. As shown, the tubes ii and iii a e supported at the same level, and it is of course so be understood the gas absorbing liquid, or reacti g solution employed in the tubes it electrically conductive. A preferred embodiment of our invention, as applied to an Orsat analyzer, also ncludes a calibratedburette leintegrally connected for communication with the series of absorption tubes ii and ill by means of a manifold it. The manifold tube it is conveniently provided with a series of con.- ventional stop-cocks ii, is and as for controlling the admission of liquid and gas into the absorption tubes of the absorption units, and a eonventional stopcock 2i also is provided in the burette i l ror controlling movement of gas and liquid between the burette it and the absorption units through the manifold'tube it.

In addition to the foregoing elements, we provide a reservoir 22 for holding a quantity of mercury 25, or similar non-reacting liquid; the reservoir 22 preferably being integrally connected to the burette M by means of tubing 23 for establishing communication between these elements and to permit the mercury 25 partially to occupy the burette and partially to occupy the reservoir 22 as Well as the tubing 2.3. A suitable stopper 24 for the mercury reservoir 22 serves to mount an electrode 26 which extends within the reservoir to adjacent the bottom thereof, and we provide a second electrode 2'1 piercing the tubing and extending into the mercury therein contained; such electrodes also being connected into one of the electrical circuits by leads 2B and 29, respectively, hereinafter described. The mercury reservoir 22 preferably is adjustable in relation to the burette I l insofar as mercury levels are concerned but once the adjustment is made for a given apparatus it requires no further adjustment.

Departing from a conventional Orsat gas ana lyzer, and for use in conjunction with the burette I4 and the mercury reservoir 22, we provide a bulb 3!! for holding a reserve supply of mercury or other non-reacting liquid; the bulb 3% being placed in communication with the burette it as well as reservoir 22 by means of a flexible tubing 3! which is controlled by a suitable pinch clamp 3'2. By raising and lowering the level bulb 3B, the levels of the mercury in the burette l4 and the mercury reservoir 12?. can readily be adjusted to any desired relationship.

In accordance with our invention, We further modify the standard Orsat gas analyzer equipment by providing means for venting the mercury reservoir 22 to the atmosphere aiiording the creation of a vacuum therein whenever desired as well as egress of the air to the atmosphere. To this end, the mercury reservoir is formed with an integral tube 33 communicating with and connected to a manifold tube 34 which is open at both ends and in which we mount a pair of magnetically operable valves and Bi for controlling admission and egress of air to and from the mercury reservoir 22 as well as controlling the vacuum applied to the mercury in the reservoir 22. Valves 3B and Lil are energized and die-energized alternately in response to the magnetization and tie-magnetization of suitable magnets and 38, respectively, which are in terposed in one of the electrical circuits hereinafter described by means of the lead lines 4| and 52, respectively. The arrangement pref-- erably is such that when magnet 38 is energized its associated valve opens and when magnet 39 is energized its associated valve 37 closes, both magnets being energized simultaneously but opposite action being had. with respect to the valves in that one opens and the other closes.

Before placing the system under automatic control, certain adjustments must be made to condition the equipment or system for automatic operation. In reviewing these adjustments, it must be remembered that any one pair of the absorption units H and I2 can be selected as the unit for holding a selected re-acting solution IS in which a portion of a sample gas will be absorbed in the operation of the analyzer apparatus, and while three sets of absorption units are illustrated in Figure 1 of the drawings, it is contemplated that but one set, or one reacting solution 15, will be utilized in testing or measuring the amount of a given gas sample that w the desired or selected absorption ti will be absorbed by such re-acting solution. he first adjustment step is to load ana yzer ith a predetermined quantity of a selected re-acting solution iii and a predetermined amount of selected non-reacting solution or liquid, such ,s mercury iii. This is readily accomp had by pour rig the different re acting solu ions into tubes l i of the absorption units through the 'ge openings or mouths at the tops thereof, the re-acting solutions assuming the levels in the tubes ii and tubes iii. The no carry is introduced into the analyzer by pour g the through bulb from which it with clamp 32 open, into the burette i l, the reservoir 22 and tube 23. After the desired amount oi mercury is placed in these elements, the clamp closed. and an auxiliary supply pou ed the bulb To condition the fur-"h r a vacuum is applied to tube to of ing up of the re-acting solution l2 above the tops thereof. With coclcs and is closed and cocks and it open, the sample to be analyzed is introduced into the system between the re-acting solution and the mercury and the main cock is tl: l and a burette reading taken. valve ill, it or is opened, depencing upun which set of absorption units is to be employed, and, with burette cock 2! open, the level of the re-acting solution in tubes ii and 1' a lo with. the re-acting solution. The stop cock con trolling the selected absorption unit is then clo and the volume of gas sample, at atmosp pressue, is then r corded by reading the cali-- bration on burette M. The stop cool: controlling the absorption unit be ng emplo if; then opened and the gas is a 9 to new be if? raising the level bulb 0-] until the r cury in the burette l-i is near the top thereof. The movable electrode 2t in the top of the insrci, reservoir 22 is then adjusted by raising lo ering the reservoir 22 and so that the e ectrc e just fails to contact the mercury in tl reservoir. It is to be observed that this tage of the adjustments toe electrodes in t i a of the absorption unit will be in contact with the reacting solution ill. Clamp of tin t 35 leading from the level bulb is then clos d, and the automatic reversing control apparatus is brought into play by closing the main and 8,5111 iliary control switches of one of the elec'rical circuits hereinafter described.

Upon closin the automatic co magnetically op rate va ve magnetically cperat valve uum is at once apolied to 1"" drawing the me cury up t burette M, an from the selected abso burette. Also, the reacting taneously rises in tube iil are no longer in contact wi' breaking the circuit but the c closes by virtue of the contact of with the electrode in reservoir to the ire-closing or the circuit, however, the magnetically operated valves 'rcuit, the

Just prior .iv and 33'; are automatically ole-energised by or. airing oi the circuit and the vacuum in eservoir 7, s releasoc by the opening of valve and aclniis n of Consequently, the level of the mercury in escrvoir 22 drops to seek its own level or natural level, or

at the same level as the mercury level in burette i i. This, the circuit is momentarily broken again and the gas is moved from the burette, by virtue of the dropping oi the mercury, into the tube Q2 of the absorption unit effecting, in turn, move- I ment of the reacting solution is partially into tube l l of the absorption unit with the result that the solution again makes full contact with electrodes l3 and the ci uit against is This cycle is repeated ago J. lid again automatically until the main or auxniary switch of the electrical circuit is opened by the operator to take the system oil the automatic control, which is usually done after the operator has checked the calibration rear on burette it a number of times and fine it the same indicating that no further abs otion or the gas by the reacting solution is is taking place. Upon el' lnating the automatic control, the operator can open the pinch clamp and lower the level bulb to a point 1103.8 the re acting solution it rises above the top of the absorption tube l2. Stop-cock 2:1 is then closed and bulb 3b lowered so that the mercury level in bulb at the same level as the mercury level in the burctte i l; and. at this point the calibration or" the burette i is again read and reco ded indicating the residual volume of the gas. The percentage of absorbed is then calculated by taking the rent between the second and first readings of the calibrations.

In Figure 2 of the accompanying drawings, we have diagrammatically illustrated one embodiment of electrical control circuit which can successfully be utilized in conjunction with the ore ferred embodiment of our invention partially shown in Figure 1. While other control circuits may be used and applied to different embodiments of our invention, the circuit shown in Figure 2 is preferred for application to an Orsat analyzer. As shown, a of leads dB and All are connected to a source of alternating current, not shown, and these leads are connected to one pair of contacts of a main switch lt to be understood that the alternating cur nt circuit may be of any desired voltage and freouency provided capacities of otl elements alter mentioned are suitable and cor espond. eferably, to avoid danger of injury fr high voltage, and as a protection to the operator, one side of the circuit is grounded as indicated at 9. The other pair of contacts of main switch :lal receive a pair of leads Ell and 52 which provide a closed circuit, and a pilot light is conveniently connected across leads 5i and 52 to assist the operator whenever he desires to make examination of conditions. The preferred electrical circuit includes an electronic tube which may be a trio-dc, tetrode, beam power amplifier, thyratron or other type of grid controlled electronic tube, and the same is interposed in the circuit across the leads 5i and The circuit also includes a rectifier tube and a grid controlled glow discharge tube bl, both associated with the tube together with a relay operated by the electronic tub-e and a relay operated by the tube Suitable adjustable resistors ti, 62 and are interposed in the circuit in association with the tubes l and er, as well as short resistors and and a condenser all as hereinafter escribecl. A secondary or auxiliary control switch for the circuit is interposed in lead 5!, as well as a fuse all for the convenience of the operator.

With both switches :38 and or closed, the filaments or" electronic tube 5% and of rectifier tube 553 become heated. In passing, it may be observed that tubes es and lit may be enclosed in a single 6 envelope and these are obtainable commercially as they are sold under the trade designations of II'YNYGT or ll'ZPlGT. The heating of the filament of tube 53 develops a direct current voltage across the adjustable resistor and the condenser which is associated with the resistor 62 0i sunlcient capacitance to typical direct current operation of the grid controlled glow discharge tube through the short resistor 35 and lead 55. The tube must be a gas vapor filled triode ignited by positive grid voltage, relative to its cathode, and capable of operating the relay 5S; tubes of this character being commercially available under the trade designations OA lG or ICZI. It is clear that the closing of the circuit places the grid of tube t l at cathode potential and that the tube passes suiiicient current to close relay and apply a direct current voltage to the glow discharge tube El, this occurring when electrodes is are in contact with the re-acting solution is in the tube ll of the absorption unit since the tube is connected with electrodes I?! through the leads 3 and Q, shown in Figure 1. Since electrode 2 is not in contact with the mercury in reservoir when the electrodes I? are in contact with the reacting solution it, positive voltage is appied to the grid of the tube 5? permitting current to pass for closing the relay 59 which applies alternating current, flowing through leads ll and 2, to the magnets 38 and. 39 for operating the valves 38 and ill of the modified Orsat anal depicted in Figure 1 of the drawings. It may be observed that we have interposed a pilot light 'lll across the leads ll and 12 to indicate to the operator the condition of this portion of the electrical circuit. It clean-of course, that the pilots and is are not essential to the operation but are only included for the convenience of the operator.

In the operation of the system, it is clear that almost simultaneously with the ignition of the tube 57 and energization of the magnets 38 and 39 as well as operation of valves 35 and 3t, the mercury rises in reservoir 22 to effect contact with electrode 26, thereby removing positive voltage from the grid of glow discharge tube 51. However, conduction of current has already commenced and, therefore, grid control has been lost and tube 52 continues to conduct current to relay 59 until the electrodes l3 break contact with the re-acting solution l5 by displacement of the same into the absorption tube 52 of the absorption unit.

Upon breaking of the circuit when electrodes 53 lose contact with the re-acting solution I5, a negative bias is applied to the grid of tube 54 shutting off the current and thus opening the relay 58 as well as its associated switch 58 which thus opens the plate circuit of the tube 5'! since the switch 58' is connected to the plate circuit of tube 51 by means of a lead ll, adjustable resistor 63 and the resistor tap lead 712. Because of the opening of the plate circuit of tube 51, the relay 59 and. its associated switch 59' also opens resulting in the de-energization of the magnets controlling the valves 3% and 37 to release the vacuum in reservoir 22 and allow the mercury which had been drawn up into the reservoir to return or drop to its former level and partially to occupy burette It. This action displaces the gas from burette M and moves it into the absorption tube I 2 which, in turn, displaces the reacting solution so that some of it occupies the reservoir tube I l to re-establish contact with the electrodes 13 therein. As a result, the circuit is again closed; the tube 54 conducts current to relay 58 to close the same as well as its associated switch 58 thus again applying plate voltage to the glow discharge tube 51. However, tube does not conduct any current until the mercury in reservoir 22 drops below the electrode 2t and breaks contact therewith to allow the grid of tube 51 to receive positive voltage. Hence, relay 59 does not close until the mercury in reservoir 22 actually breaks contact with the electrode 25 and when it does the cycle is completed and repeats itself again and again until the operator opens switch 61.

Summarizing the operation of the automatic reversing control of our invention, as applied to an Ol'sat analyzer, it will be observed that in each cycle the following occurs: (1) Mercury is drawn up by vacuum into reservoir 22, thus drawing gas from the absorption tube [2 of the absorption unit; (2) electrodes l3 break contact with the reacting solution l5 as it leaves tube ll of the absorption unit; and (3) the triode 5A ceases to conduct current and the magnets controlling the valves 36 and ill are de-energized until the mercury in the reservoir 22 has returned to its initial level just below the contact or electrode 26. Simultaneously, gas i displaced from burette M to the tube ill and the reacting solution returns to its initial position in tube H to make contact again with electrodes 53. These steps recur again and again until operations cease upon the opening of the switch It should be observed that although the volume of the gas in burette l4 decreases as absorption of the gas occurs, there is no interference with the operation of the system since the cycle is controlled by the liquid levels in tube I I and reservoir While we have illustrated the preferred embodiment of our invention with electrodes is contacting the reacting solution in tube l I and electrode 2h contacting the mercury in reservoir 22, operations may be carried out by placing the electrodes l3 in the tubes it of the absorption units, adjacent the tops thereof, instead of in tubes H, as shown, and b mounting the electrodes 26 and 2 1 in the top of the burette i l, and then by modifying the electrical circuit of Figure 2 slightly. With these dispositions of the electrodes, the short resistor 64 should be changed so as to be disposed across the leads 3 and 9 which connect the electrodes it into the circuit, and the tap lead to adjustable resistor ill connected to lead 8 should be removed and connected to ground; while lead ll should be connected to the tap to adjustable resistor 6|. The tap lead containing short resistor 65 and leading from line 29 to the adjustable resistor 52 should be connected to ground while the grounded line 28 should be connected to the tap of the adjustable resistor 62. With these changes in the circuit, cyclical operations will occur as before. However, the first arrangement is preferred because of possible danger from explosions where explosive gases or mixtures are being analyzed. Moreover, special equipment must be used in the second arrangement whereas in the former almost a conventional Orsat analyzer may be employed.

In Figure 3 of the drawings, we have illustrated diagrammatically, a modified electrical circuit em 'iloy' lg but one triode and an impulse relay with suitable resistors, auxiliary control switch and fuse, for utilization with the equipment shown in Figure 1. For convenience, we have illustrated schematically in Figure 3 an Orsat analyzer apparatus of somewhat the conventional type which includes a pair of absorption tubes Hi and 32 for holding the re-acting solution H5, with electrodes H3 mounted in tube iii, together with a calibrated burette H4 supported adjacent the absorption tubes and in con nunication therewith by means of the manifold tube lit in which a conventional stopcock ill is mounted. This equipment also includes a stop-cock E25 for the burette lit and a mercury reservoir i223 integrally connected for communication with the burette lid by means of the tube Electrodes iiiil and iii are mounted respectively in the reservoir H22 and the tube E23 In this modification, one of the electrodes H3 is connected by lead 8 to electrode liii while the other electrode H3 is connected to the modified electrical circuit by means of the lead :3, as hereinafter described. Similarly, electrode llli is connected through lead to the electrical circuit of Figure 3. As in the preferred embodiment, the reservoir i vented to the atmosphere through an open-ended manifold tube, not shown, in which the magnetically valves are mounted; the magnets for ".g such valves being energized and dei response to the closing and opening 2 all not shown. To th' end, we

' ..r of lines and l ll for con- H alternating current from a source therenot shown, to one of contacts of a main switch 5 the circuit being grounded as inclii -hl for the protection of the operator from high voltage. A pair of leads iii and I52 are connected '0 the other pair of contacts of main switch i l-ll to provide a closed impulse relay circuit wh; h includes a triode l5a and an impulse relay its having a pair of contacts i5! and for transmitting current impulses to the le de Mi and connected to the magnets, not shown, for oper g the valves which control the vacuum in the air admission to r: rcury reservoir Hi2. A suitable auxiliary switch ifi'l, together with a suitable fuse are connected in e circuit, as shown.

In the operation of the automatic reversing control as modified by the electrical circuit illustrated in Figure 3 of the drau as, gas sample to be a ,lyzed introduced i o the Orsantirough stop-cock liil alter the react ng sol on Hi5 and the mercury H5, or other nonreacting liquid has been admitted, In this arrange vlent, when the auxiliary switch lb? of the automatic reversing control is closed, the reactsolution lit in tube ill will be aking cont :t with electrodes 5 but the merci y in reservoir i132 will not be making contact with electrode iiii. Line voltage will be app ied to the grid of tube the tube will conduct current for actuatin impulse relay which, in turn, eil'ects energization of the magnets controlling the valves in th me ifold tube in communication with the reservoh, through the contaste and of the relay When a longer in contact therewith, the contacts I51 and I58 of the impulse relay I56 are not energized so that the magnets controlling the valves in the manifold tube in communication with the reservoir 522 are ale-energized, and air is admitted to the reservoir i222 the vacuum is released. As a result, the mercury in reservoir iZZ drops and seeks initial level with the consequent moving of the re-acting solution H back into tube ill to an extent that electrodes Hill are again contacted. The cycle then repeats itself with the impulse contacts i5ll and i553 again becoming energized and de-energized recurrently, and the liquids and gas being moved alternately to and fro until the total amount of gas that can be absorbed by the re-acting' solution H5 is eii'ected at which time the operator opens the switch it? to break the circuit.

Another modified electrical circuit for automatically reversing the flow of fluids in a closed system, such in an Orsat analyzer apparatus, is diagrammatically illustrated in Figure 4 of the annexed drawings. The principal differences in this modified circuit from the circuit illustrated in Figure 2 are that the rectifier tube is eliminated in the modified circuit, and the grid controlled glow discharge tube thereof requires negative grid voltage instead of positive voltage to prevent conduction of current to its relay and prevent its operation. In describing the circuit of Figure 4, reference will be made from time to time to the elements of the Orsat apparatus depicted in Figure l of the drawings with which the modifled circuit of Figure 4 is adapted to be used for automatic reversing control of the fluids in the apparatus. Before alluding to the circuit of Figure 4, it may be observed that the usual adjustments of the Orsat apparatus are made prior to placing the same on the circuit for automatic reversing control, as hereinabove explained.

As shown, the second modified electrical circuit of our invention, as applied to an Orsat analyzer or like equipment, preferably is provided with elements powered by direct current. The circuit includes a triode tube 254 and a grid controlled now discharge tube 251; the tube 25 operating a relay 253 and its associated switch 258 while tube 25's operates relay 259 and its associated switch 2%. The electrodes l3 of the Orsat analyzer are connected through leads 3 and ii to the triode 25d of the modified circuit; the electrodes H to the tube 257 through leads 28 and 29; and the magnetically operated valves and Eli are connected to the relay switch 259' through the leads ii and 32. Requisite adjustabl resistors EM, 262 and 253 are provided for controlling the magnitude of the current applied to the tubes, and a suitable switch 26? is interposed in the circuit for opening and closing the same whenever desired. When the switch is in open position, electrodes iii are making contact with the reacting solution 95 in tube ll while electrode 28 is not in contact with the mercury in reservoir 22. The grid of triode 25 i is at cathode potential. When the switch 2% is closed, positive voltage is applied to the plate of tube 25d and current flows through the coil of relay 258 closing the switch 2523. The closing of switch 258 eifects the application of a positive voltage through small resistor 27H to the plate of grid controlled glow tube 257i. Since the contact 26 is open, the grid of tube Eel is substantially at cathode potential and current starts to flow closing relay 25 9 and its associated switch 259 thus energizing the magnets controlling valves Eli and 31 through leads 4| and 42. Upon opening of valve 36 and simultaneous closing of valve 31 through energization of magnets 38 and 39, a vacuum is created or applied in reservoir 22 drawing mercury from the burette Hi, the gas from tube M2 and re-acting solution from tube ll, all as previously explained. Electrical contact between electrode 2'5 and the mercury in reservoir 22 is then established and as a result a negative bias is applied to the grid of glow tube 251. However, since the tube 25'! is conducting direct current, grid control is lost until conduction stops. Therefore, tube 251 still continues to conduct current to relay 259. When most of the gas has been withdrawn from tube I2, the electrodes it are no longer in contact with the reacting solution so that a negative bias is applied to the grid of tube 25d and the current flowing to relay 256 is cut off opening the switch 258'. This stops the current through tube 25'! opening relay switch 259' and the magnets 38 and 39 are lie-energized opening valve Sl and closing valve 36 to release the vacuum in reservoir 22 by the admission of air. Consequently, the mercury in reservoir 22 returns to its initial level moving the gas back into tube l2 and, in turn, part of the re-acting liquid back into tube l i to make contact again with the electrodes 53. Since current again flows from tube 25 to its relay 258 and positive voltage is again applied to the tube 25? to re-establish grid control, the tube 251' is again conditioned for action but current does not flow in tube 25'! until the mercury 25 in reservoir 22 drops below electrode 26 removing the negative bias on the grid of tube 251. When the mercury has dropped to its initial level the cycle repeats.

From the above examples, it is obvious that automatic reversing control is obtained by the momentary make and break between the electrodes i3 and reacting solution i5, and the electrode 26 and the mercury 25. controlling the valves 35 and 3V are energized they remain energized until solution electrodes ill momentarily break contact. Once the magnets controlling valves 36 and 3? become de-energized they remain de -energized until the mercury electrode 2t momentarily breaks contact. It is to be understood that it is not necessary to employ mercury in the system, since other materials or liquids that are suitable electrical conductors may be used as long as a clear break is afforded between the same and the electrode 26.

We have indicated above that our hereinabove described invention is not limited to application to an Orsat analyzer. As a further adaptation of our invent on, reference is made to Figure 5 of th accompanying drawings wherein a preferred embodiment of the invention is shown as adapted to a Toepler pump, a device utilized in laboratories for transporting gases or fluids without contamination from one apparatus to another for further analysis or treatment with other chemicals or reacting solutions. As illustrated in Figure 5, we provide a chamber 3! I for holding a quantity of a gas to be transferred to other equipment Without contamination, the gas having been received in chamber 3H from an Orsat analyzer or other apparatus, with stop cocks 312 and 3| 3 in tubes- 32' and H5, respectively, closed and with a predetermined quantity of mercury already introduced into the system. The equipment also includes a pair of mercury reservoirs Sit and 3|! in communication With one another by means of integral tubing M8; the reservoir SIS having an electrode 3! 9 sealed in the top thereof and the Once the magnets,

1 l reservoir 3!? having an electrode 372i sealed in its top. Reservoirs tit and are supported at different levels with reservoir tit at a slightly lower elevation than reservoir fill, and at such elevation that when the mercury rises therein its highest level will be below the level of the tip oi the electrode 532i in the reservoir 3H. The difference between elevations of these two reservoirs should be equal to or greater than the absolute pressure of the vacuum system, as expressed in terms of height of mercury, or other confining liquid.

In accordance with our invention, the reservoir 316 is vented to the atmosphere through tubing 333 and a manifold which is open at both ends and in which is mounted a pair of magnetically operable valves and this arrangement being similar to the manifold 34 and valves and 3'! of the embodiment of our invention shown in Figure 1 of the drawings in conjunction with mercury reservoir 2'3 of that embodiment. As shown, a magnet is provided for controlling val e and a magnet 33.) for controlling valve r; magnets and being interposed in the electrical circuit and being energized ole-energised in response to momentary make and break. of the circuit hereinafter described. In. the Toepler pump embodiment of our invention, we also provide a by-pass tube Mil between chamber till and reservoir 3, and an outlet tube from mercury reservoir 3!! which leads through a bulb sill to discharging tube through tube 3L". As shown, a third electrode is mounted. in the tubing 38B connecting mercury reservoirs and 3H, and electrodes 322i are connected into the electrical circuit selected by means of leads 345, 34'! and MB, respectively.

Preliminarily to placing the Toepler pump embodiment of our invention under automatic control, the system to which the gas from the chamber 31! is to be delivered is initially evacuated and part of the gas is transferred from chamber 3!] by opening valve with valve or cook 313 closed, thus equalizi pressures between chamber fill and the discharging or outlet tube 343. Valve 3|! is then closed ...-d the control circuit turned on. With the circuit closed, valve 336 opens and valve closes upon energization of the control and and when contact between. the electrode and the mercury in reservoir Bil is about to break, by-pass tube 34!! open and from chamber 3M passes into reservoir 3i"? filling the therein. When contact between electrode and the mercury breaks, the valve closes and valve opens because of the da-energiaation of the magnets 33!! thus rele the vacuum holding the mercury in reservoi 5i returning the mercury to reservoir l l to overflow the same slightly pushing the through bulb M2 to the discharging At this point, the mercury breaks contact with electrode did in reservoir 3E6, valve 335 opens and valve closes creating a vacuum again in reservoir M6 to draw the mercury again from the reservoir 31?, thus repeating the cycle. The and 339 are connected into the selected electrical circuit by of the leads 301 la and il lila, respectively.

It may be observed that the electrical circuit of Figure 2 of the accompanying drawings can be used in conjunction with the Toe oler pump embodiment of our invention if the resistor 64 thereof is replaced by a conductor or lead, while the electrical circuit of Figure 3 may be employed without change. Moreover, the circuit of Figure 4 of the drawings may be utilized with the Toepler pump embodiment by replacing resistor 264 with a conductor. It may be added that the tubing iii-ii from the top of reservoir 3H to the bulb il lil is preferably made a capillary tubing so that when the mercury returns from reservoir all to reservoir in the second stage of each cycle, the mercury column will break thus preventing syphoning of mercury from the reservoir 317? into the line B ll. If it is desired to reduce the frequency of the cycle of operations, a restriction can be placed in the tubing between the valve manifold 3- 1 and the reservoir FAG.

In Figure 6 or the accompanying drawings, we have illustrated diagrammatically another modification of electrical circuit for use with either the Orsat analyzer or the Toepler pump embodiments of our invention. shown, and as applied to the Great analyzer embodiment of the invention, this modified circuit includes a main control switch l lii of which one pair of contacts are connected to a source of alternating current, not shown, by means of the leads l ill and Ml. The other pair of contacts of main switch 448 are engaged by a pair or main circuit leads :15! and the circuit including a grid-controlled vacuum tube or time iiifil of su table capacity to operate a relay t a rectifier for producing direct current voltage, and a conventional filtering condenser connected across a potentiometer which is d; rated by the re crence numerals lGl and The *esistors and l t-l of the circuit are grid resistors for the triode 45 t, as indicated by the diagrammatic showing of Figure 6. As in the oth r circuits described above, we provide an au .ry switch for the convenience of the operator JlllCil designated by the reference numeral l-ll, and the conductors from the various elements of the Orsat analyzer are interposed into the circuit as in the previously described 0'" uits. For example and with reference to Figures 1 and 5, conductors B and i), respectively, from the electrodes iii of the absorption unit i 5, l2, are connected to the grid of triode 45% through resistors and 1%; the conductors 28 and 23 from the electrodes 23 and El are connected into main circuit line and the conductors all and from the magnets controlling the valves and ill are connected to the contacts of the relay switch operated by relay Initially, the circuit closer w h t re-acting solution of the absorption in in contact with the electrodes l3 this stage, the electrode 28 is of contact with t; rcp y or the res ervoir Under these con: the grid of triode QM is connected to the cathode through resistor lfi l and conductors i l. Moreover, since there is no contact bet, the electrode 26 and the mercury in lSJl"VOll' grid bias across resistor and the see is at cathode pote Switch closed to place the s in under versing control and, as a result, t ducts sufficient current to relay a fraction of the negative potential of resistor 462 to the grid of triode 454, thus reducing the current conducted through relay 458 to an intermediate value but not sufficiently low as to allow the relay switch 458' to open. The mercury continues to rise in reservoir 22 until contact is entirely broken between the reacting solution in tube I l and the electrodes I3 and, at this point the electrical circuit is broken through resistors 463 and 464 while the grid is connected to the most negative potential through resistor 463 and leads 28 and 29 from electrodes 26 and 21. This negative bias is of sufficient value to reduce the current through relay 458 to zero resulting in the opening of the relay switch 458' and breaking of current supply to the magnets controlling valves 36 and 31. As a result, valve 36 closes and valve 31 opens with a venting of mercury reservoir 22 and resulting rise of the re-acting solution in tube I I of the absorption unit to contact electrodes l3 again. This again places an intermediate negative bias on the grid of triode 454 allowing an intermediate value of current to flow to relay 458 but not of sufiicient value to close relay switch 458. The mercury continues to fall in reservoir 22 until out of contact with electrode 26 and, at this oint, the circuit through resistors 463 and 464 is again opened placing the grid of triode 454 at cathode potential through resistor 464; whereupon full current again flows to relay 458 and relay switch 458' closes to repeat the cycle.

It will be clear that the hereinabove last described circuit takes advantage of a well known characteristic of relays; namely, the power required to close a relay is far greater than the power required to hold the relay closed.

We claim:

1. Orsat apparatus comprising in combination a mercury reservoir and a U-type absorption tube, a burette in communication with said absorption jother of said valves connecting tube, a conduit establishing communication with said mercury reservoir and said burette, a first pair of electrodes consisting of a first electrode mounted within said reservoir and a second electrode disposed in said conduit, a second pair of electrodes disposed in one arm of said absorption tube, a pair of valves in spaced relationship electrically actuated by a pair of magnets, one of said valves connecting to a vacuum means, the to the atmosphere, a conduit connecting said valves, a tube establishing communication between said valves and said reservoir, and an electrical circuit containing all of said electrodes and said magnets.

2. Orsat apparatus as defined in claim 1 in which the electrical circuit comprises an electronic tube connected to said second pair of electrodes, a glow-discharge tube, a first relay operated by said electronic tube for applying direct current voltage to said glow-discharge tube when said second pair of electrodes are connected into the circuit and the circuit is closed, and a second relay operated by said glow-discharge tube for applying alternating current to said magnets to actuate said valves.

3. Orsat apparatus as defined in claim 1 in which the electrical circuit comprises a triode, and an impulse relay operated by said triode for energizing said magnets to actuate said valves.

LIONEL S. GALSTAUN. DELBERT D. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,147,607 McMillan et a1 Feb. 14, 1939 2,273,993 Rockwood Feb. 24, 1942 

